WO2011102832A1

WO2011102832A1 - A system and method for cooling an electrical device in a closed air volume

Info

Publication number: WO2011102832A1
Application number: PCT/US2010/024510
Authority: WO
Inventors: John Janik
Original assignee: Power Integration Consuliting, Inc.
Priority date: 2010-02-18
Filing date: 2010-02-18
Publication date: 2011-08-25

Abstract

A method for cooling is disclosed, the method including but not limited to supplying a first portion of a closed volume of air to a first electrical device; discharging the first portion of the closed volume of air from the first motor into a first heat exchanger; discharging the first portion of the closed volume of air from the first heat exchanger into the closed volume of air; supplying a second portion of the closed volume of air to a second electrical device; discharging the second portion of the closed volume of air from the second motor into a second heat exchanger; and discharging the second portion of the closed volume of air from the second heat exchanger into the closed volume of air. A system is provided for performing the method.

Description

Title: A SYSTEM AND METHOD FOR COOLING AN ELECTRICAL DEVICE IN A CLOSED AIR VOLUME

RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Application No. 61/101,017 filed September 29, 2008; the full disclosure of with is hereby incorporated by reference herein in its entirety.

FIELD OF THE DISCLOSURE

[0002] The field of the present disclosure relates to cooling systems.

BACK GROUND OF THE DISCLOSURE

[0003] One typical method in cooling of a traction type motor (for example, a GE Model 752 Traction Motor) for hazardous areas such as those conditions found in drilling and mining applications is to use a "closed loop" system of air circulation with a cooling method for a motor. In such a closed loop cooling system, heated exhaust air from a motor is cooled and fed back directly to the air intake of the motor in a closed pneumatic loop.

[0004] For many years in the drilling industry the direct current (DC) traction machines, which were either deck mounted or even within the hull of a drilling vessel, have been cooled by simply recirculation of the exhaust air (pre-heated due to the electrical and mechanical losses of the machine) back to the intake of the ventilation blower via passing through a "radiator" style water to air heat exchanger.

[0005] The cooling system requires a filter system because of the carbon dust being created due to the brush area riding the commutator, a differential pressure switch for monitoring the status of this filter, a flow or pressure switch which insures positive pressure, and "make-up" air to ensure dry clean air is supplied in case of leaks within the closed loop system heat exchange system.

[0006] Since the "chiller", also referred to herein as "radiator", is an integral part of the "closed loop" heat exchange system, if a leak is encountered then chilled water from the heat exchanger used to chill the circulating air loop is contained within the closed system of the motor. Because of this machine being a "DC" or "direct current" type of motor, voltage is maintained on the commutator via the brush connection to the commutator bars and can be in voltage values exceeding 700 VDC.

[0007] If a water leak occurs typically a "flash over" condition will proceed which creates damage to the DC armature and sometimes is so severe that the motor must be removed from the vessel in which it is contained and replaced or repaired prior to restarting of that particular application.

[0008] Other problems that can and many times do exist are leaks that occur in the closed loop enclosure they often reoccur due to cracked welds, vibration or leaking gasket material where the enclosure fastens onto the exhaust parts and intake blower area. With a positive displacement fan at up to 10 inches of water column in the commutator box area, and since the exhaust ducting is directly tied back to the input of the blower system, therefore a "closed loop" type of arrangement, any leaks become negative pressure relative to atmospheric pressure therefore a suction effect is found at any leak. In other words, if a leak occurs, it "sucks" the surrounding atmospheric pressure air into it. If the leak is large enough to allow sufficient external non re-circulating air to enter, the result is an over temperature within the "partially" closed-loop system.

[0009] Many end users use the "raw water" or sea water as the actual cooling water, and if a water leak occurs, the salt water enters into the DC machine very quickly and can cause permanent damage in which case the motor must be replaced in its entirety. Other methods of the cooling water is to use re-circulated fresh water, but require an additional water-to-water heat exchanger installed to cool the fresh water which is a closed loop cooling system, cooled via a salt water/fresh water, water-to-water chilling or another cooling system, such as a water-to-water heat exchanger. Additional costs, complexity and statistically more components, connectors, etc. make a system less reliable.

[0010] With the closed loop system of cooling for hazard type atmospheric conditions the make-up air and the first volumes of "closed loop" air must be brought in from an area that is considered "non-hazard" atmospheric supply. In some closed loop cooling systems, a minimum of three (3) volumes of air must also be exchanged prior to "sealing off" the closed loop system, every time prior to the start-up of the DC machine adding to the complexity and cost(s) to the system.

[0011] For a closed loop filtration system, due to the "D" size of the carbon dust from the current carrying brush assembly, the filter must be a potted type that ensures no dust particles sneak between the filter and filter frame work assembly, therefore premature clogging of the radiator coils and fins. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 depicts an illustrative embodiment of a system for cooling an electrical device on a naval vessel;

[0013] FIG. 2 depicts a particular illustrative embodiment of a cooling system for a closed volume of air containing motors and other electrical devices; and

[0014] FIG. 3 depicts an illustrative embodiment of a firewater pumping and flushing system on a naval vessel.

DETAILED DESCRIPTION

[0015] Another illustrative embodiment provides a system and method for cooling an electrical device, such as motor exhaust air prior to discharging the air into a closed volume of air in a motor space, such as an equipment room on a naval vessel. The exhaust air cooling reduces the recycling of leakage water and particulate waste in the motor that in a closed loop intake air cooling system would blow waste particles such as carbon dust from rotor brushes and water leaking from the motor, directly back into the motor or other device being cooled, as would be the case for closed loop cooling system or a front cooled cooling system. In a particular illustrative embodiment, first and second electrical devices, such as a first and second motor and a first and second heat exchanger are enclosed in an equipment room, also referred to in the present disclosure as an equipment operation station (EOS). The EOS contains a closed volume of air in which the first and second motor and the first and second heat exchanger operate. In a particular illustrative embodiment, if a leak exists, the water does not enter into the motor. In another particular embodiment, an additional pressure drop in the system due to the change in pressure across the radiator or heat exchanger is compensated for by increasing the power rating of a cooling fan in the heat exchangers.

[0016] In another particular embodiment, additional desired cooling of the exhaust air is calculated once the exchanged volume of air in the space is given by the shipyard, the ambient temperature of the compartment is required and not to exceed American Bureau of Shipping (ABS) requirements and the desired total temperature of the motors is used, and again does not exceed ABS rules for propulsion machine limits.

[0017] In another particular embodiment, filtration of the exhaust carbon dust still occurs but due to less restrictions on the physical sizing of the radiator and also less cooling requirements due to having an "open loop" system, the fins and cooling coils of the heat exchanger are not so restricted therefore allowing larger grain size material to pass more easily. In another particular embodiment, the complexity and sealing is less problematic and does not exceed typical requirements of a standard 752 style blower/cooling system. In another particular embodiment, either salt water (raw water) or freshwater can be used as the cooling median in the heat exchangers.

[0018] hi another particular embodiment, a conservative design in the "delta T" (change of temperature across the radiator) is provided so that even with one heat exchanger completely taken out of this system, sufficient cooling can be achieved for the system as a whole. In other words, with one heat exchanger not functioning, the system is designed such that the all electrical devices, including but not limited to electronics and motors in the EOS continue to operate at full capacity without overheating problems in any of the motor compartments.

[0019] In another particular embodiment, the cooling system and method provide an ABS rating of DP2, that is, with a single point of failure in the EOS, such a losing a single heat exchanger, the dynamic position motors in the EOS which operate to steer a naval vessel can still operate without over heating. In another particular embodiment, the system and method are simpler, have less moving parts, smaller, less complex and approximately 1/3 of the price of the conventional closed-loop cooler. This does not include the cost savings in plumbing, other heat exchanger devices, etc.

[0020] In another particular embodiment, a method is disclosed for cooling an electrical device, the method including but not limited to, supplying a first portion of a closed volume of air to a first electrical device; discharging the first portion of the closed volume of air from the first motor into a first heat exchanger;

discharging the first portion of the closed volume of air from the first heat exchanger into the closed volume of air; supplying a second portion of the closed volume of air to a second motor; discharging the second portion of the closed volume of air from the second motor into a second heat exchanger; and discharging the second portion of the closed volume of air from the second heat exchanger into the closed volume of air. In another particular embodiment, the first heat exchanger has a cooling capacity greater than necessary to cool the first portion of the closed volume of air discharging from the first motor. In another particular embodiment, the second heat exchanger has a cooling capacity greater than necessary to cool the second portion of the closed volume of air discharging from the second motor.

[0021] In another particular embodiment, the first heat exchanger has a cooling capacity greater than necessary to cool the first portion of the closed volume of air discharging from the first electrical device, such as a motor and the second heat exchanger has a cooling capacity greater than necessary to cool the second portion of the closed volume of air discharging from the second electrical device, such as a motor. In another particular embodiment, the first heat exchanger has a cooling capacity sufficient to cool the first portion of the closed volume of air discharging from the first heat exchanger and the second portion of the closed volume of air discharging from the second heat exchanger. In another particular embodiment, the second heat exchanger has a cooling capacity sufficient to cool the first portion of the closed volume of air discharging from the first heat exchanger and the second portion of the closed volume of air discharging from the second heat exchanger.

[0022] In another particular embodiment of the method, the method further includes but is not limited to mixing with the closed volume of air, the first portion of the closed volume of air discharging from the first heat exchanger and the second portion of the closed volume of air discharging from the second heat exchanger. In another particular embodiment of the method, the method further includes cooling the closed volume of air with the first portion of the closed volume of air discharging from the first heat exchanger and the second portion of the closed volume of air discharging from the second heat exchanger. In another particular embodiment of the method, the method further includes but is not limited to cooling in the first heat exchanger, the first portion of the closed volume of air discharging from the first motor into the first heat exchanger. In another particular embodiment of the method, the method further includes but is not limited to cooling in the first heat exchanger, the closed volume of air including the second portion of the closed volume of air discharged from the second heat exchanger.

[0023] In another particular embodiment, a system is disclosed for cooling, the system including but not limited to a first air blower in pneumatic

communication with a first portion of a closed volume of air and a first electrical device, such as a motor; a first heat exchanger in pneumatic communication with the first portion of the closed volume of air discharging from the first motor; a first air discharger in pneumatic communication with the first heat exchanger and the closed volume of air for discharging the first portion of the closed volume of air from the first heat exchanger into the closed volume of air; a second air blower in pneumatic communication with a second portion of the closed volume of air and a second electrical device, such as a second motor; a second heat exchanger in pneumatic communication with the second portion of the closed volume of air from the second motor into a second heat exchanger; and a second air discharger in pneumatic communication with the second heat exchanger and the closed volume of air for discharging the second portion of the closed volume of air from the second heat exchanger into the closed volume of air.

[0024] In another particular embodiment of the system, the first heat exchanger has a cooling capacity greater than necessary to cool the first portion of the closed volume of air discharging from the first motor. In another particular embodiment of the system, the second heat exchanger has a cooling capacity greater than necessaiy to cool the second portion of the closed volume of air discharging from the second motor. In another particular embodiment of the system, the first heat exchanger has a cooling capacity greater than necessary to cool the first portion of the closed volume of air discharging from the first motor and the second heat exchanger has a cooling capacity greater than necessary to cool the second portion of the closed volume of air discharging from the second motor. [0025] In another particular embodiment of the system, the first heat exchanger has a cooling capacity sufficient to cool the first portion of the closed volume of air discharging from the first heat exchanger and the second portion of the closed volume of air discharging from the second heat exchanger. In another particular embodiment of the system, the second heat exchanger has a cooling capacity sufficient to cool the first portion of the closed volume of air discharging from the first heat exchanger and the second portion of the closed volume of air discharging from the second heat exchanger. In another particular embodiment of the system, the closed volume of air mixes the first portion of the closed volume of air discharging from the first heat exchanger and the second portion of the closed volume of air discharging from the second heat exchanger.

[0026] In another particular embodiment of the system, the closed volume of air is heated by the first portion of the closed volume of air discharging from the first heat exchanger and by second portion of the closed volume of air discharging from the second heat exchanger. In another particular embodiment of the system, the first heat exchanger cools the first portion of the closed volume of air discharging from the first motor into the first heat exchanger. In another particular embodiment of the system, the first heat exchanger cools the closed volume of air including the second portion of the closed volume of air discharged from the second heat exchanger. In another particular embodiment of the system, the closed volume of air is enclosed within an equipment room, also referred to as and equipment operation station. In another particular embodiment of the system, the closed volume of air is enclosed within an integral structure of a naval vessel. [0027] Turning now to FIG. 1, in a particular illustrative embodiment, a naval vessel 100 floats in sea water 101. The vessel contains an equipment operation station 102 or EOS which is connected to EOS electronics 104 via electrical conductor 111. In another particular embodiment, the EOS is a sealed portion of the vessel structure where only electrical connecting are exposed to prevent damage to the electrical components inside of the EOS. The EOS electronics in a particular embodiment include but are not limited to a silicon controlled rectifier (SCR). In another particular illustrative embodiment, the EOS electronics are positioned adjacent and in thermal communication with heat sink 106. The heat sink is positioned in pneumatic communication with a stream of outside air 108 which is provided to supply air to an engine 110 on the naval vessel which may be a diesel or gasoline engine. The engine exhaust exits via vessel vent 112 which provide a conduit for vented air 114 from the engine.

[0028] Turning now to FIG. 2, a depiction of an illustrative embodiment of the equipment operating station (EOS) 200 is shown. The EOS walls 201 provide an enclosure for a closed volume of equipment room air 202. The EOS contains a first motor 202 and a first heat exchanger 219 which are in pneumatic

communication. Heated exhaust air 210 from the first motor is fed to the first heat exchanger. The heated air is cooled by the heat exchanger and exhausts 221 into the EOS closed volume of air. Air 207 is supplied to the first motor from the EOS closed volume of air by blower 204. In a particular embodiment, the first heat exchanger is equipped with a chiller such as water pump 225 for cool water heat exchange with the heated air entering the first heat exchanger. The EOS also includes but is not limited to a second motor 217 and a second heat exchanger 213 which are in pneumatic communication with each other. Heated exhaust air 215 from the second motor is fed to the second heat exchanger. The heated air from the second motor is cooled by the second heat exchanger and exhausts 223 into the EOS closed volume of air. Air 208 is supplied to the second motor from the EOS closed volume of air by blower 209. In a particular embodiment, the second heat exchanger is equipped with a chiller such as water pump 211 for cool water heat exchange with the heated air entering the first heat exchanger. In another particular embodiment the cooling system further includes but is not limited to a filter 113 for removing dirt and particulate waste particles from the closed volume of air. The first and second electrical devices or motors exhaust dirt, carbon dust from electric rotors and brushes and water from leaks when they occur, all of which are exhausted into the closed volume of air. The filter helps to remove the dirt, carbon dust from electric rotors and brushes and water from leaks from the closed volume of air.

[0029] In another particular embodiment, the EOS further contains a fire water system 300, as described in conjunction with FIG. 3. Turning now to FIG. 3, a depiction of a particular illustrative embodiment, a fire water system (FWS) 300 is shown. As shown in FIG. 3, the FWS includes but is not limited to a salt water source such as sea water 305 in fluid communication with pump 205 and valve 313. Valve 313 is also in fluid communication with fresh water pump/source 307. The fresh water pump is in fluid communication with fresh water source. The fresh water pump is a low pumping capacity pump which slowly pumps fresh water into the fresh water flush tank during the long periods between fire fighting operations. The valve 313 alternately provides fluid communication between the FWS heat exchanger 214 and either sea water 305 or fresh water 307, A valve controller 318 which in one illustrative embodiment includes but is not limited to a processor and computer readable medium containing instructions executed by the processor and memory for storing data in the computer readable medium. The valve controller is provided for controlling the position of the valve 313 to alternately provide fluid communication between the FWS heat exchanger 214 and either sea water 305 or fresh water 307. In another illustrative embodiment, the valve controller is a manual valve.

[0030] During fire operations, such as a fire or fire drill, which occur infrequently, the valve 313 is set by valve controller 318 to connect the heat exchanger 214 to sea water 305 via sea water pump 205. The sea water travels through sea water conduit 302 where the sea water is pumped by pump 205 through valve 313 to heat exchanger 214. The sea water pump has sufficient pumping power to supply sufficient sea water to a standard naval fire hose during fire fighting operations. In a particular embodiment the sea water pump 205 has pumping capacity of 100 gallons/minute. After fire fighting operations, valve 313 is positioned to provide fluid communication between the heat exchanger and the fresh water source/pump to rinse the corrosive sea water from the heat exchanger where it remains until the next fire fighting operation during which large volumes of sea water are pumped through heat exchanger 214. Heat exchanger 214 is used to chill air exhaust from motor 202 in the EOS. Blower 204 provides air to electric motor 202. Electric motor 202 power fire pump 318 which pump sea water from sea 305 through hose 320 where it is expelled as a sea water stream 322. [0031] The illustrations of embodiments described herein are intended to provide a general understanding of the structure of various embodiments, and they are not intended to serve as a complete description of all the elements and features of apparatus and systems that might make use of the structures described herein. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. Other embodiments may be utilized and derived there from, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Figures are also merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

[0032] Such embodiments of the inventive subject matter may be referred to herein, individually and/or collectively, by the term "invention" merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

[0033] The Abstract of the Disclosure is provided to comply with 37 C.F.R. § 1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.

Claims

A method for coolmg, the method comprising:

Supplying a first portion of a closed volume of air to a first electrical device;

Discharging the first portion of the closed volume of air from the first motor into a first heat exchanger;

Discharging the first portion of the closed volume of air from the first heat exchanger into the closed volume of air;

Supplying a second portion of the closed volume of air to a second electrical device;

Discharging the second portion of the closed volume of air from the second electrical device into a second heat exchanger; and

Discharging the second portion of the closed volume of air from the second heat exchanger into the closed volume of air.

The method of claim 1, wherein the first heat exchanger has a cooling capacity greater than necessary to cool the first portion of the closed volume of air discharging from the first electrical device.

The method of claim 1, wherein the second heat exchanger has a cooling capacity greater than necessary to cool the second portion of the closed volume of air discharging from the second electrical device.

4. The method of claim 1, wherein the first heat exchanger has a cooling capacity greater than necessary to cool the first portion of the closed volume of air discharging from the first electrical device and the second heat exchanger has a cooling capacity greater than necessary to cool the second portion of the closed volume of air discharging from the second electrical device.

5. The method of claim 1, wherein the first heat exchanger has a cooling capacity sufficient to cool the first portion of the closed volume of air discharging from the first heat exchanger and the second portion of the closed volume of air discharging from the second heat exchanger.

6. The method of claim 1 , wherein the second heat exchanger has a cooling capacity sufficient to cool the first portion of the closed volume of air discharging from the first heat exchanger and the second portion of the closed volume of air discharging from the second heat exchanger.

7. The method of claim 1, further comprising:

Mixing with the closed volume of air, the first portion of the closed volume of air discharging from the first heat exchanger and second portion of the closed volume of air discharging from the second heat exchanger.

8. The method of claim 7, further comprising: Heating the closed volume of air with the first portion of the closed volume of air discharging from the first heat exchanger and second portion of the closed volume of air discharging from the second heat exchanger.

9. The method of claim 1, further comprising:

Cooling in the first heat exchanger, the first portion of the closed volume of air discharging from the first motor into the first heat exchanger.

10. The method of claim 9, further comprising:

Cooling in the first heat exchanger, the closed volume of air including the second portion of the closed volume of air discharged from the second heat exchanger.

11. A system for cooling, the system comprising:

A first air blower in pneumatic communication with a first portion of a closed volume of air and a first electrical device;

A first heat exchanger in pneumatic communication with the first portion of the closed volume of air discharging from the first electrical device; A first air discharger in pneumatic communication with the first heat exchanger and the closed volume of air for discharging the first portion of the closed volume of air from the first heat exchanger into the closed volume of air;

A second air blower in pneumatic communication with a second portion of the closed volume of air and a second electrical device; A second heat exchanger in pneumatic communication with the second portion of the closed volume of air from the second electrical device into a second heat exchanger;

and

A second air discharger in pneumatic communication with the second heat exchanger and the closed volume of air for discharging the second portion of the closed volume of air from the second heat exchanger into the closed volume of air.

12. The system of claim 11, wherein the first heat exchanger has a cooling capacity greater than necessary to cool the first portion of the closed volume of air discharging from the first electrical device.

13. The system of claim 11 , wherein the second heat exchanger has a cooling capacity greater than necessary to cool the second portion of the closed volume of air discharging from the second electrical device.

14. The system of claim 11 , wherein the first heat exchanger has a cooling capacity greater than necessary to cool the first portion of the closed volume of air discharging from the first electrical device and the second heat exchanger has a cooling capacity greater than necessary to cool the second portion of the closed volume of air discharging from the second electrical device.

15. The system of claim 1 1, wherein the first heat exchanger has a cooling capacity sufficient to cool the first portion of the closed volume of air discharging from the first heat exchanger and the second portion of the closed volume of air discharging from the second heat exchanger.

16. The system of claim 11 , wherein the second heat exchanger has a cooling capacity sufficient to cool the first portion of the closed volume of air discharging from the first heat exchanger and the second portion of the closed volume of air discharging from the second heat exchanger.

17. The system of claim 11, wherein the closed volume of air mixes the first portion of the closed volume of air discharging from the first heat exchanger and the second portion of the closed volume of air discharging from the second heat exchanger.

18. The system of claim 17, wherein the closed volume of air is heated by the first portion of the closed volume of air discharging from the first heat exchanger and by second portion of the closed volume of air discharging from the second heat exchanger.

19. The system of claim 11, wherein the first heat exchanger cools the first portion of the closed volume of air discharging from the first electrical device into the first heat exchanger.

20. The system of claim 19, wherein the first heat exchanger cools the closed volume of air including the second portion of the closed volume of air discharged from the second heat exchanger.

21. The system of claim 11 , wherein the closed volume of air is enclosed within an equipment room.

22. The system of claim 11, wherein the closed volume of air is enclosed within an integral structure of a naval vessel.

23. The system of claim 11, the system further comprising a first electrical section containing heat producing electrical devices and a second electrical section containing control electronics for the electrical devices, wherein the heat producing electrical devices are motors and the control electronics are in thermal communication with a heat sink.

24. The system of claim 23, wherein the heat sink further comprises a highly thermal conductive material coated with a non corrosive material.

25. The system of claim 23, wherein the highly conductive material is copper and the non corrosive material is nickel.

26. The system of claim 23, wherein the heat sink is in thermal

communication with an air supply for an engine. The system of claim 23, wherein the control electronics are electrically rated greater than twenty five percent higher than a normal duty cycle for the control electronics.

The system of claim 23, wherein the control electronics are electrically rated greater than one hundred percent higher than a normal duty cycle for the control electronics.

The system of claim 23, further comprising:

An engine air supply in pneumatic communication with the second section comprising the control electronics.